People most at-risk for Alpha-1 are those who have a family member with Alpha-1 and those from ethnic backgrounds in which Alpha-1 is known to be common. However, Alpha-1 occurs worldwide.

It is estimated that 100,000 people in the U.S. have Alpha-1 deficiency, and over 1 million people have it worldwide. Also, people who have a personal history or family members with signs and symptoms of Alpha-1 are also at greater risk.

Medical professionals in North America and Europe as well as the World Health Organization agree that Alpha-1 is largely unrecognized or misdiagnosed.

There are several reasons for this:

• Not all people with Alpha-1 develop signs and symptoms. This is called "incomplete penetrance."
• There is extreme variation in the symptoms of Alpha-1 and how mild or severe they are — even within the same family. This is called "variable expression,"
• How and when Alpha-1 develops can be affected by exposure to environmental risks.
• Many of the complications related to Alpha-1 are common and can have other causes.

Over 1 million people wordwide have severe Alpha-1 with serious medical complications. There are probably many more who suffer from Alpha-1, since many people with Alpha-1 are never diagnosed.

About 116 million people worldwide are Alpha-1 carriers. Carriers have one altered copy and one normal copy of the AAT gene. The normal copy is usually enough to prevent symptoms of the condition. However, carriers can pass on Alpha-1 to their children if their partner also happens to be a carrier. About 1 in 10 to 1 in 33 people in the U.S. are thought to be carriers.

Who Develops Alpha-1?

Men and women are at equal risk for Alpha-1. People with certain ethnic backgrounds, such as Northern European and Ashkenazi Jewish, are at higher risk than people from other ethnic backgrounds, such as Asian.